The present invention relates to mixed metal oxide (amm)oxidation catalysts.
Mixed metal oxide (MMO) catalysts are well known for (amm)oxidation of alkanes and alkenes to unsaturated carboxylic acids or nitrites. For example, U.S. Pat. No. 6,407,280 discloses MMO catalysts containing Mo or W; V or Ce; Te, Sb or Se; as well as other metals, e.g., Nb, and promoted by at least one of Ni, Pd, Cu, Ag and Au.
U.S. Pat. No. 7,875,571 discloses a method for preparing MMO catalysts by contacting an MMO with water alone at elevated temperature or water comprising a metal oxide precursor to form a modified MMO, followed by calcining the modified MMO.
U.S. Pat. No. 7,304,014 teaches preparing MMO catalysts by, after calcination, doing one or more chemical and/or physical treatments such as extraction with oxalic acid in methanol, extraction with an alcohol followed by densification by extra pressing, cryo-grinding followed by extraction with oxalic acid in methanol, and others.
Prior art processes for preparing selective MMO catalysts are complicated and can involve a large number of steps. Each additional step incurs additional costs, and can lead to catalysts that give relatively more variation in selectivity during use. It would be desirable to have a relatively simple method of preparing selective MMO catalysts.